Overview
IEC 61196-1-126:2022 specifies the electrical test method for measuring the corona (partial discharge) extinction voltage of coaxial communication cables under defined environmental conditions. The standard documents the test principle, equipment, sample preparation and reporting requirements used to confirm insulation integrity and to support production quality control and product specification compliance.
Key measurable terms defined in the standard include:
- PDIV (partial discharge inception voltage) – the lowest RMS voltage at which PD ≥ 5 pC is detected when increasing voltage.
- PDEV (partial discharge extinction voltage) – the highest RMS voltage at which PD ceases when decreasing voltage from PDIV.
Key Topics
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Sample preparation: Samples are typically 0.6 m to 1.5 m long (1 m recommended). Procedures are provided for flexible, semi‑flexible, semi‑rigid and unjacketed semi‑flexible cable types, including required stripping, trimming and grounding arrangements (e.g., rolling back shield, trimming insulation, heat‑shrink covers, and grounding wire of 0.8 mm diameter).
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Test principle: A low‑frequency (40 Hz–60 Hz) AC voltage is slowly raised between inner and outer conductors until partial discharge of at least 5 pC is detected, then slowly reduced to determine extinction voltage. A band‑pass filtering and detection chain is used to identify PD pulses.
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Equipment and calibration: Required equipment includes a high‑voltage source, detector/oscilloscope, partial discharge adapter, optional altitude chamber, and instrumentation capable of detecting PD of 5 pC or less. Calibration shall follow IEC 60270 to verify PD magnitude measurement.
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Procedure parameters: Voltage ramp rate when increasing should be about one‑tenth of expected PDIV per second, but not less than 50 V/s and not more than 500 V/s. When decreasing, a rate of approximately 50 V/s is used. Where specified, tests are performed at reduced pressure or varied temperature in an altitude test chamber.
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Repeatability and reporting: Unless otherwise specified, five samples are each measured five times and PDIV/PDEV values are averaged. Test reports must include test conditions (temperature, pressure, humidity), equipment used, ramp rate and RMS results.
Applications
- Insulation verification during product development and type approval.
- Production quality control (QC) to detect manufacturing defects that cause partial discharges.
- Environmental condition testing, including altitude and temperature influences on corona extinction behaviour.
Related Standards
- IEC 60270 - High‑voltage test techniques – Partial discharge measurements (calibration and measurement technique reference).
- IEC 61196-1 - Coaxial communication cable - Part 1: Generic specification for terminology and general requirements.
This part of IEC 61196 provides a practical, repeatable method for assessing corona extinction voltage (PDEV) in coaxial cables to support compliance, reliability assessment and quality assurance processes.
Open preview (PDF)Coaxial communication cables - Part 1-126: Electrical test methods - Corona extinction voltage
